Dermatology Flashcards
What are the topical steroids used in eczema?
Mild: hydrocortisone
Moderate: Eumovate (clobetasone butyrate)
Potent: Betnovate (betamethasone)
Very potent: Dermovate (clobetasol propionate)
How is psoriasis managed?
First-line:
A potent corticosteroid applied once daily plus vitamin D analogue applied once daily
should be applied separately, for up to 4 weeks as initial treatment
Second-line: if no improvement after 8 weeks then offer:
A vitamin D analogue twice daily
Third-line: if no improvement after 8-12 weeks then offer either:
A potent corticosteroid applied twice daily for up to 4 weeks, or
A coal tar preparation applied once or twice daily
short-acting dithranol can also be used
What is the name of a thick emollient?
Diprobase
Which viruses cause eczema herpeticum?
HSV
VZV
What causes Stevens-Johnson syndrome?
Medications:
Anti-epileptics
Antibiotics
Allopurinol
NSAIDs
Infections:
Herpes simplex
Mycoplasma pneumoniae
CMV
HIV
How is Stevens-Johnson syndrome treated?
Steroids
Immunglobulins
Immunosuppressants
What causes molluscum contagious?
Molluscum contagiosa virus
What are a key feature of Coxsackie virus?
Painful mouth ulcers, particularly on the tongue
What conditions are associated with erythema nodosum?
IBD
Sarcoidosis
Lymphoma
Leukaemia
What causes erythema nodosum?
Hypersensitivity reaction:
Strep throat infection
Gastroenteritis
Mycoplasma pneumoniae
TB
Pregnancy
Medications such as OCP and NSAIDs
What causes erythema multiforme?
Most commonly a hypersensitivity reaction.
Viral infections, notably associated with:
HSV
Mycoplasma pneumoniae
Medications
What does the rash look like in erythema multiforme?
“Target lesions”
What conditions is seborrhoeic dermatitis associated with?
HIV
PD
What are anti fungal creams?
Clotrimazole
Miconazole
What causes seborrhoeic dermatitis?
Malassezia yeast
What is the pathophysiology of psoriasis?
Chronic autoimmune condition
Skin changes caused by the rapid generation of new skin cells resulting in abnormal build up of the skin in those areas
What is Auspitz sign?
Small points of bleeding where the plaques are scraped off in psoriasis
What exacerbates psoriasis?
Trauma
Alcohol
Drugs: BB, lithium, antimalarials, NSAIDs, ACE-inhibitor, infliximab
Withdrawal of systemic steroids
What are the types of psoriasis?
Plaque psoriasis: most common type in adults
Guttate psoriasis: most common type in children
Pustular psoriasis
Erythrodermic psoriasis
How long do children have to isolate with measles?
4 days after symptoms resolve
What is the most common complication of measles?
Otitis media
How long do children have to stay off school with scarlet fever?
24 hours after starting antibiotics
Which conditions are associated with Group A strep?
Post strep glomerulonephritis
Acute rheumatic fever
Scarlet fever
Who long do children stay off school with rubella?
5 days after the rash disappears
What is congenital rubella syndrome?
Deafness
Blindness
Congenital heart disease
What is a complications of Parvovirus B19?
Aplastic anaemia
Encephalitis or meningitis
Pregnancy complications including fatal death
Rarely hepatitis, myocarditis, nephritis
What causes roseola infantum?
Human herpesvirus 6
Human herpesvirus 7 (less common)
How does roseola infantum present?
High fever >40
Rash once fever settles
What is the pathophysiology of acne vulgaris?
Chronic inflammation with or without localised infection in pockets within the skin known as the pilosebacous unit
Increased production of sebum, trapping of keratin, blockage of the pilosebaceous unit
Androgens cause sebum release
Swollen and inflamed units are called comedones.
How does isotretinoin work?
Reduces sebum, inflammation and bacterial growth
Which COCP is most effective for acne?
Co-cyprindiol
What are SE of isotretinoin?
Dry skin and lips
Photosensitivity of skin to sunlight
Depression, anxiety, aggression, suicidal ideation, Steven Johnsons syndrome
How long do children stay off school for with chickenpox?
Until they have all crusted over (around 5 days after rash appears)
What are the risks of chickenpox in pregnancy?
<28 weeks: developmental problems in the foetus
Around delivery: life-threatening VZV infection
How is staphylococcal scalded skin syndrome treated?
IV abx
What is Nikolsky sign in staphylococcal scalded skin syndrome?
Gentle rubbing of the skin causes it to peel away
What is the characteristic starting patch in pityriasis rosea?
Herald patch usually on torso
What is a sedating antihistamine?
Chlorphenamine
What is the parasite in headlice?
Pediculus humanus capitus
What is the treatment of headlice?
Dimeticone lotion applied to hair and left for 8 hours then washed off
Repeated 7 days later
Special fine combs
What are the causes of impetigo?
Staphylococcus aureus (always in bullies)
Streptococcus progenies (less common)
What is the management of impetigo?
Non bullous:
Hydrogen peroxide 1% cream
Topical fusidic acid
Oral flucloxacillin if widespread or severe
Bullous:
Oral/IV flucloxacillin
How long do you keep children off school for impetigo?
Until all lesions have healed or 48 hours after antibitoics
What causes scabies?
Scarcoptes scabei
What is the treatment of scabies?
Permethrin cream
Fill body, leave on for 8-12 hours
Repeat 1 week later
Treat all household contacts
What causes ringworm?
Trichophyton
What are the types of ringworm?
Tinea capitis: scalp
Tinea pedis: feet
Tinea cruris: groin
Tinea corporis: body
Onchymycosis: fungal nail infection
How do you treat fungal nail?
Oral terbinafine
Amorolfine nail lacquer for 6-12 months
What are the types of basal cell carcinoma?
Nodular (most common)
Superficial (younger)
Morpheaform (aka sclerosing or infiltrating)
What is the most common type of cancer in the world?
Basal cell carcinoma
What does a nodular basal cell carcinoma look like?
Pearly, shiny papule or nodules with small telangiectasis, rolled borders and a depressed centre
What does a superficial basal cell carcinoma look like?
Plaque or patch of well defined, scaly, pink skin, some pigmented. Most commonly on the trunk and in extremities
What are the types of biopsy in skin cancer?
Excisional
Incisional
Shave
Punch (lowest diagnostic accuracy)
What are the histological features of BCC?
Basophilic aggregations of basaxoid keratinocytes with large nuclei and scant cytoplasm
Clefts of tumour tissue
Peripheral palisading of nuclei
Apoptotic cells
How is BCC treated?
Low risk:
Complete surgical excision
Electrodesiccation and curettage
Topical 5-fluorouracil
Cryotherapy
Photodyanmic therapy
High risk:
Mohs micrographic surgery (preserves as much of the surrounding skin as possible)
Simple resection with adjunct radiotherapy
What is Bowen’s disease?
SCC in situ. The cancerous cells are confined to the epidermis and can progress to invasive SCC
What is the most common type of skin cancer in Fitzpatrick V and VI skin types?
SCC
What is the management of acne?
Mild to moderate:
A 12-week course of topical combination therapy should be tried first-line:
A fixed combination of topical adapalene with topical benzoyl peroxide
A fixed combination of topical tretinoin with topical clindamycin
A fixed combination of topical benzoyl peroxide with topical clindamycin
Topical benzoyl peroxide may be used as monotherapy if these options are contraindicated or the person wishes to avoid using a topical retinoid or an antibiotic.
Moderate to severe:
A 12-week course of one of the following options:
A fixed combination of topical adapalene with topical benzoyl peroxide
A fixed combination of topical tretinoin with topical clindamycin
A fixed combination of topical adapalene with topical benzoyl peroxide + either oral lymecycline or oral doxycycline
A topical azelaic acid + either oral lymecycline or oral doxycycline
Combined oral contraceptives (COCP) are an alternative to oral antibiotics in women
Oral isotretinoin (only under specialist supervision)
How is acne classified?
Mild: open and closed comedones with or without sparse inflammatory lesions
Moderate acne: widespread non-inflammatory lesions and numerous papules and pustules
Severe acne: extensive inflammatory lesions, which may include nodules, pitting, and scarring
What does SCC look like?
Growing nodule
Bleeding lesion, itching, crusting
Texture or colour change
Ulceration
Pain
Firm to palpate
What are high risk features for SCC?
> 2mm deep or >20mm wide
Site: face, ear, genitals, hand, feet
Recurrence
Immunosuppressed individual
Poor differentiation and perineurial invasion on histology
High tumour budding
How do you investigate skin cancer?
Dermatoscope
Biopsy and histology
US of lymph nodes, CT and MRI if metastasis supsected
How is Bowen’s disease managed?
Destructive therapies:
Cryotherapy (liquid nitrogen to freeze)
Topical 5-fluorouracil
How is invasive SCC managed?
Conventional surgical excision (Mohs micrographic surgery aka margin controlled excision)
How is metastatic SCC managed?
Surgical excision, radiotherapy, chemotherapy
Immunotherapy drugs
How is malignant melanoma classified?
In situ: confined to the epidermis
Invasive: spread to the dermis
Metastatic: spread to other tissues
Where does melanoma arise from?
The melanocyte later of the skin, normally situated in the basal layer of the epidermis
What is a signature mutation in SCC?
P53 tumour suppressor gene
How do melanomas present?
A symmetrical shape
B order irregularity including poorly defined margins
C olour change and variation
D iameter of the mole, most are >6mm
E volving e.g. changing in size, shape or colour
What is the first sign of melanoma?
Change in a previous mole, freckle or a new lesion arising in a normal patch of skin
What is diagnostic for melanoma?
Excisional full thickness skin biopsy with lateral margin 2-3mm
Sentinetl node biopsy when Breslow thickness >0.8mm
What is prognostic indication in melanoma?
Thickness
Use Breslow thickness score
0= in situ
1= <2mm thickness
2= >2mm thickness
3= spread to involve local lymph nodes
4= metastatis to distant
What is the management of melanoma?
Wide local excision
0.5cm margin for stage 0
What are the subtypes of melanoma?
Superficial spreading melanoma: most common type, longer in situ phase, initially grows horizontally
Nodular melanoma: most aggressive type, invade vertically, rapidly growing, often bleed or ulcerate
Lentigo maligna melanoma: directly related to sun damage, discoloured patch of skin that grows over time
Acral lentiguous melanoma: originates on the palms, soles, under the nails, flat pigmented lesion that slowly enlarges, often diagnosed late due to the location
What layers does cellulitis affect?
Dermis and subcutaneous
What is erysipelas?
More superficial than cellulitis, commonly affecting the face
What are the common causes of cellulitis?
Staph aureus
Strep pyogenes
What is more likely than bilateral cellulitis?
More likely to have venous insufficiency, lipodermatosclerosis or another cause
When should cellulitis be reviewed in the community?
After 48 hours
What do you treat cellulitis with if penicillin allergy?
Doxycycline
When is prophylaxis given in cellulitis?
2 separate episodes in last 12 months
Give low dose penicillin or erythromycin if pen allergic
Which cause of cellulitis is linked to necrotising fasciitis?
Clostridium perfringens
How should non-healing ulcers be investigated?
Tissue biopsy to confirm malignancy
How do arterial ulcers present?
Predominantly on lower extremities, near end-arteries, particularly the toes, heels and lateral malleolus
Severe resting pain due to ischaemia especially at night. Worse when legs elevated
Pale, dry and gangrenous with cool surrounding skin
Sharply defined and a deep “punched out” appearance
Loss of hair on surrounding skin (shiny appearance)
Diminished or absent pulses
What APBI indicates arterial insufficiency?
<0.8
What causes venous ulcers?
Chronic venous insufficiency resulting in increased venous pressure and impaired tissue oxygenation, triggering inflammation and tissue damage
This increased venous pressure most commonly results from venous reflux due to faulty valve function developing as a long term sequelae of DVT or varicose veins
How does a venous ulcer present?
Typically medial malleolus
Aching or heaviness in affected limb
Worsens with prolonged standing and improves with legs elevated
Shallow with irregular borders
Accompanied by oedema, erythema, brown pigment deposition in the surrounding skin
Lipodermatosclerosis and atrophy blanche (white scarring with dilated capillaries)
Skin likely to be warm
Pulses generally remain normal
How are venous ulcers managed?
Compression bandage
What are more specialist treatments of eczema?
Sedating antihistamines
Phototherapy
Oral steroids
Paste bandaging
Azathioprine
Ciclosporin
Where should you look for psoriasis?
Extensor surfaces
Scalp
Nails
What are treatments for psoriasis?
Emollients
Topical steroids
Tar
Vitamin D analogue e.g. calcipotriol
Vitamin D analogues
Dithranol
Phototherapy
Ciclosporin
TNF a blockers e.g. infliximab
Methotrexate
Where else can malignant melanoma occur?
Choroid of the eye
CNS
GI tract
What is the bacteria in acne?
Propionibacterium acnes
Where would you look for a SCC?
Ear
Lips
How are pressure sores graded?
1 = non-blanching erythema over intact skin
2 = partial thickness skin loss
3 = full thickness skin loss, extending into subcutaneous fat
4 = extensive destruction with involvement of muscle, supporting tissue
What are risk factors for pressure sore?
Elderly
CVD
Obesity
Poor nutrition
Immobility
Smoking
Neurologically impaired
Faecal incontinence
Urinary incontinence
How do you manage pressure sores?
Nutrition
Antibiotics if infected
Regular dressings
Need for debridement
Pain relief
Patient repositioning
Tissue viability referral
Pressure relieving mattress/chair
What are differentials for lichen sclerosus?
Localised scleroderma
Vitiligo
SCC
Bowen’s
Lichen planus
Vulval intraepithelial neoplasia
How do you treat lichen sclerosis?
Topical steroids
Topical emollients
Lubricants
